Ryegrass,hairy vetch and milk vetch were selected as green manures to study their effects on soil fertility for growing spring corn in Southern China.Results show that compared with the control,three green manures increased the organic matter contents and available nutrients of rhizosphere soil,while ryegrass and hairy vetch showed better effects than milk vetch.Furthermore,hairy vetch was better than ryegrass and milk vetch as for improving the available nutrients,and hairy vetch was about equal to ryegrass regarding the effect on improving the organic matter in rhizosphere soil.Preliminary tests prove that the ryegrass and hairy vetch can be used as the predominant green manure species of winter fallow field.